As a large-format photographer, I am always looking for film bargains. I have read in various places that relatively speaking, film isn’t much more expensive today than it was in the 1950s. Be that as it may, I still find it costly. Enter oddball films.
I am not alone in experimenting with odd films. Lots of people shoot x-ray for instance. My preference is for duplicating film, specifically the aerographic type. Kodak made quite a few, some to order for the client. I happened on a 9.5″ x 500′ roll of Kodak 2421 and after several years of experimenting I’m finally getting some predictable results.
Duplicating film is orthochromatic so that it can be used under red darkroom light. It is also very slow and is designed to be developed in printing chemicals. I have used as little as 1 minute in Ansco 130 for this film (though I don’t recommend it because ultra rapid development results in pinholes in the emulsion).
Kodak 2421 rated at 5. 8×10. Busch 11″ lens. 3 sec @f/6.8
Orthochromatic emulsions have been around for a long long time. The distinctive look of Civil War portraits are due in part to the orthochromatic nature of the emulsions used in the 1860s. Couple the film with an old brass lens and you get a modern version of those portraits. You can get similar results, but without the convenience of darkroom development, by using a Cyan filter on ordinary film.
Blue light varies throughout the day. If you’re shooting around noon, the film will behave like a panchromatic film but be nearly grainless. Ortho film isn’t sensitive to red light which means reds are darker and blues lighter. I have found that ortho films marketed by Adox and the like are not nearly as pronounced in effect as duplicating film. I would imagine this is to make the film more usable in a variety of shooting conditions. In the morning and afternoon I meter through a blue filter to mimic the film emulsion.

This one is also Kodak 2421. Aero Ektar 178mm lens. 5×7 film. 1.5 sec @ f/11
Generally, I use D-76 1:1 and tray develop under red light in the darkroom. I agitate gently and continuously for the first minute, then 10 seconds each subsequent minute. For N development, I use 7.5 minutes @ 70 degrees F.
